1. Field of the Invention
The invention relates to a heat exchanging system and, more particularly, to a heat exchanging system that exchanges heat between refrigerant flowing through a vapor compression refrigeration cycle and a temperature regulated portion of which the temperature is regulated.
2. Description of Related Art
In recent years, hybrid vehicles, fuel cell vehicles, electric vehicles, and the like, that travel by using the driving force of a motor become a focus of attention as one of measures against environmental issues. In such vehicles, electrical devices, such as a motor, a generator, an inverter, a converter and a battery, exchange electric power to generate heat. Therefore, these electrical devices need to be cooled. Then, there has been suggested a technique that utilizes a vapor compression refrigeration cycle, which is used as a vehicle air conditioner, to cool a heat generating element.
For example, Japanese Patent Application Publication No. 2010-81704 (JP 2010-81704 A) describes a technique for cooling a charger as follows. A circulation passage that connects the charger with a radiator and through which coolant circulates is formed. Air is delivered to the radiator as a cooling fan is driven, and coolant flowing through the radiator effectively releases heat. Coolant that has released heat in the radiator flows through the charger as a pump is driven. Heat is exchanged between the charger and the coolant. Japanese Patent Application Publication No. 2005-90862 (JP 2005-90862 A) describes a cooling system that includes a heat generating element cooling unit for cooling a heat generating element in a bypass passage that bypasses a decompressor, an evaporator and a compressor of an air-conditioning refrigeration cycle.
Incidentally, as the temperature of a battery decreases, a chemical change is suppressed inside the battery and then a power density decreases, so it may be difficult to ensure battery output when the temperature of the battery is low. In addition, as a battery characteristic, when the battery is left standing in a low temperature range, the electrical resistance inside the battery increases, and the input efficiency decreases, so the charging time increases, and the battery charging efficiency decreases. Therefore, in a low temperature environment, such as cold places having a low outside air temperature, the battery is desirably warmed moderately.
In relation to a technique for warming a battery mounted on a vehicle, for example, Japanese Patent Application Publication No. 2009-257254 (JP 2009-257254 A) describes a system that stores heat in a chemical thermal storage material while a vehicle is travelling and heats a battery with the heat stored in the chemical thermal storage material at the time when the vehicle is started. Japanese Patent Application Publication No. 10-12286 (JP 10-12286 A) describes a system that utilizes heating fluid for heating a vehicle cabin in heating a battery. Japanese Patent Application Publication No. 2010-272289 (JP 2010-272289 A) describes a system that heats refrigerant supplied to a battery by utilizing waste heat from a converter and a charger.
When a battery is charged by an external power supply, it is required to heat the battery in a low temperature environment as described above. On the other hand, the temperature of the battery increases with the duration of charging, so the battery needs to be cooled. Therefore, there is a system contradiction that heating of the battery and cooling of the battery are performed in the same system. There is a method of heating a heated object with a heater; however, an exclusive heating device and an exclusive heat exchanger need to be provided, causing an increase in cost and the size of the system, so it is not appropriate to be mounted on a vehicle.